WORCSETER - Lt. Gov. Timothy P. Murray Friday bowed out of a possible run for governor in 2014, citing the demands of campaigning, serving in elected office and his desire to spend more time with his wife and two young daughters.

“I’ve decided that I am not going to run for governor,” said the former Worcester mayor, ending speculation among many and hope among his supporters that he would try to succeed Gov. Deval L. Patrick.

“It’s something I have been thinking about for some time,” Mr. Murray said. He said the decision came after sitting down to talk it through with his wife, Tammy, and with key supporters since the Christmas holidays.

“I love the job of being lieutenant governor. I loved the job of being mayor. I loved the job of being a city councilor,” he said of his 15 years in elected office. But the demands of running a campaign and serving in office can require 15- and 16-hour days, six and seven days a week, he said, and would leave him little time to be with his family.

“When I look at the next 20 months, how do I do my job with the issues in my portfolio? How do I run a campaign that my supporters and the people of Massachusetts deserve, and be a father to two daughters, who are 6 and 7 years old, and a husband to my wife, and I don’t know how I could do all of those things well,” Mr. Murray said.

He said he expected that if he ran for governor he would win, and that he would then have four years of equally demanding work.

“It really comes down to a family decision, and that is where I need to focus,” Mr. Murray said. He did not rule out future runs for political office.

He said controversies over a car accident on Interstate 190 in November 2011 and his previous political involvement with Michael E. McLaughlin, the disgraced former director of the Chelsea Housing Authority, played no role in his decision.

Mr. Murray’s decision is expected to create a wide-open field for the Democratic nomination for governor. Besides Mr. Murray, state Treasurer Steven Grossman has been viewed as a potential candidate.

Mr. Murray, 44, said he has been involved in nine campaigns for elected office, running for Worcester City Council twice, mayor three times, in a Democratic primary for lieutenant governor, in the general election in 2006 and in the 2010 re-election campaign.

“There are very few people across the state who know the demands that this requires. I’m not independently wealthy. I can’t finance my own campaign, my wife has to work, and we have got two daughters,” he said.

Mr. Murray had $391,000 in his campaign account as of Dec. 31. Mr. Grossman had about $442,203, officials said.

During the 2010 campaign, “for 15 months I was gone six or seven days a week from morning to night,” Mr. Murray said. “My daughters are at an age now that they ask what am I doing,” he said, and he tells them “working.”

“You are always working, Daddy,” he said they tell him. “My brothers all coach their kids, and this year my daughter asked me, ‘Daddy, how come you don’t coach?’ ” he said. “Those things kind of hit you.”

He continued, “To me, this is a chapter. It’s not the end of the book. I may be a fairly young politician, but I am an old father.”

Mr. Patrick said he has mixed feelings about Mr. Murray’s decision and that he was ready to back Mr. Murray as a candidate for governor.

“If he chose to be a candidate, I was with him. He was my candidate. I’ve seen him in action. I’ve seen his intellect and heart, and I hope his time will come,” Mr. Patrick said.

“I so respect the decision he is making and that he is thinking about his family first. He has been such a magnificent lieutenant governor, and I hope one day he will be governor,” Mr. Patrick said in an interview Friday.

“He’s got a beautiful family and cares about those girls so much and wants to be a part of their lives,” the governor said. He said campaigns are demanding, not just on the candidate, but on the candidate’s entire family.

“They are always demanding in terms of time and physical stamina, but they are often demanding in terms of emotional stamina, because they can be so nasty,” Mr. Patrick said, recalling the toll his first campaign took on his family. “Our kids were older and out of the house in the first campaign, and it still took a toll” on them, Mr. Patrick said.

Mr. Murray, he said, “is a true partner” taking a leadership role in the administration on veterans services, homelessness and retention of military bases. He said he has also been at the center of dealing with transportation and infrastructure development and brought real-world knowledge of local government to bear on numerous municipal reforms.

“He understands how these systems work, and he is very, very good at bringing people together and getting to yes,” Mr. Patrick said of the role Mr. Murray has played in the administration.

The governor said he does not believe the controversy over Mr. Murray’s accident and involvement with Mr. McLaughlin, while difficult issues for Mr. Murray to confront, prompted his decision.

“No doubt they have taken an emotional toll, but I would not say they were central factors in these decisions. They are controversies, and in the midst of them it seems that this is it. Then you weather them and get back to work and keep producing, and that is what he has done,” the governor said.

In a letter sent to his supporters Friday, Mr. Murray explained that he has been “grappling with how I can juggle a campaign and work duties with my responsibilities as a husband and the father of two active and beautiful daughters, Helen and Kati, who are 7 and 6 years old.”

In that note he talked about his accomplishments and pride in projects such as the Gateway Cities program that brought new state educational and economic assistance to the midsize cities of the state.

He recalled advice he got years ago when he played football at St. John’s High School.

“My high school coach always told our football team to finish the game strong. I intend to work with Gov. Patrick over the next 22 months to finish this second term strong and build a record of generational responsibility,” Mr. Murray told his supporters.